Configuring a GitHub or GitHub Enterprise identity provider

Configure a github identity provider to validate user names and passwords against GitHub or GitHub Enterprise’s OAuth authentication server. OAuth facilitates a token exchange flow between OKD and GitHub or GitHub Enterprise.

You can use the GitHub integration to connect to either GitHub or GitHub Enterprise. For GitHub Enterprise integrations, you must provide the hostname of your instance and can optionally provide a ca certificate bundle to use in requests to the server.

The following steps apply to both GitHub and GitHub Enterprise unless noted.

Configuring GitHub authentication allows users to log in to OKD with their GitHub credentials. To prevent anyone with any GitHub user ID from logging in to your OKD cluster, you can restrict access to only those in specific GitHub organizations.

About identity providers in OKD

By default, only a kubeadmin user exists on your cluster. To specify an identity provider, you must create a custom resource (CR) that describes that identity provider and add it to the cluster.

OKD user names containing /, :, and % are not supported.

Registering a GitHub application

To use GitHub or GitHub Enterprise as an identity provider, you must register an application to use.

Procedure

  1. Register an application on GitHub:

  2. Enter an application name, for example My OpenShift Install.

  3. Enter a homepage URL, such as https://oauth-openshift.apps.<cluster-name>.<cluster-domain>.

  4. Optional: Enter an application description.

  5. Enter the authorization callback URL, where the end of the URL contains the identity provider name:

    1. https://oauth-openshift.apps.<cluster-name>.<cluster-domain>/oauth2callback/<idp-provider-name>

    For example:

    1. https://oauth-openshift.apps.openshift-cluster.example.com/oauth2callback/github

  6. Click Register application. GitHub provides a client ID and a client secret. You need these values to complete the identity provider configuration.

Creating the secret

Identity providers use OKD Secret objects in the openshift-config namespace to contain the client secret, client certificates, and keys.

Procedure

  • Create a Secret object containing a string by using the following command:

    1. $ oc create secret generic <secret_name> --from-literal=clientSecret=<secret> -n openshift-config

    You can alternatively apply the following YAML to create the secret:

    1. apiVersion: v1
    2. kind: Secret
    3. metadata:
    4.   name: <secret_name>
    5.   namespace: openshift-config
    6. type: Opaque
    7. data:
    8.   clientSecret: <base64_encoded_client_secret>

  • You can define a Secret object containing the contents of a file, such as a certificate file, by using the following command:

    1. $ oc create secret generic <secret_name> --from-file=<path_to_file> -n openshift-config

Creating a config map

Identity providers use OKD ConfigMap objects in the openshift-config namespace to contain the certificate authority bundle. These are primarily used to contain certificate bundles needed by the identity provider.

This procedure is only required for GitHub Enterprise.

Procedure

  • Define an OKD ConfigMap object containing the certificate authority by using the following command. The certificate authority must be stored in the ca.crt key of the ConfigMap object.

    1. $ oc create configmap ca-config-map --from-file=ca.crt=/path/to/ca -n openshift-config

    You can alternatively apply the following YAML to create the config map:

    1. apiVersion: v1
    2. kind: ConfigMap
    3. metadata:
    4.   name: ca-config-map
    5.   namespace: openshift-config
    6. data:
    7.   ca.crt: |
    8.     <CA_certificate_PEM>

Sample GitHub CR

The following custom resource (CR) shows the parameters and acceptable values for a GitHub identity provider.

GitHub CR

  1. apiVersion: config.openshift.io/v1
  2. kind: OAuth
  3. metadata:
  4.   name: cluster
  5. spec:
  6.   identityProviders:
  7.   - name: githubidp (1)
  8.     mappingMethod: claim (2)
  9.     type: GitHub
  10.     github:
  11.       ca: (3)
  12.         name: ca-config-map
  13.       clientID: {...} (4)
  14.       clientSecret: (5)
  15.         name: github-secret
  16.       hostname: ... (6)
  17.       organizations: (7)
  18.       - myorganization1
  19.       - myorganization2
  20.       teams: (8)
  21.       - myorganization1/team-a
  22.       - myorganization2/team-b
1This provider name is prefixed to the GitHub numeric user ID to form an identity name. It is also used to build the callback URL.
2Controls how mappings are established between this provider’s identities and User objects.
3Optional: Reference to an OKD ConfigMap object containing the PEM-encoded certificate authority bundle to use in validating server certificates for the configured URL. Only for use in GitHub Enterprise with a non-publicly trusted root certificate.
4The client ID of a registered GitHub OAuth application. The application must be configured with a callback URL of https://oauth-openshift.apps.<cluster-name>.<cluster-domain>/oauth2callback/<idp-provider-name&gt;.
5Reference to an OKD Secret object containing the client secret issued by GitHub.
6For GitHub Enterprise, you must provide the hostname of your instance, such as example.com. This value must match the GitHub Enterprise hostname value in in the /setup/settings file and cannot include a port number. If this value is not set, then either teams or organizations must be defined. For GitHub, omit this parameter.
7The list of organizations. Either the organizations or teams field must be set unless the hostname field is set, or if mappingMethod is set to lookup. Cannot be used in combination with the teams field.
8The list of teams. Either the teams or organizations field must be set unless the hostname field is set, or if mappingMethod is set to lookup. Cannot be used in combination with the organizations field.

If organizations or teams is specified, only GitHub users that are members of at least one of the listed organizations will be allowed to log in. If the GitHub OAuth application configured in clientID is not owned by the organization, an organization owner must grant third-party access to use this option. This can be done during the first GitHub login by the organization’s administrator, or from the GitHub organization settings.

Additional resources

Adding an identity provider to your clusters

After you install your cluster, add an identity provider to it so your users can authenticate.

Prerequisites

  • Create an OKD cluster.

  • Create the custom resource (CR) for your identity providers.

  • You must be logged in as an administrator.

Procedure

  1. Apply the defined CR:

    1. $ oc apply -f </path/to/CR>

    If a CR does not exist, oc apply creates a new CR and might trigger the following warning: Warning: oc apply should be used on resources created by either oc create —save-config or oc apply. In this case you can safely ignore this warning.

  2. Obtain a token from the OAuth server.

    As long as the kubeadmin user has been removed, the oc login command provides instructions on how to access a web page where you can retrieve the token.

    You can also access this page from the web console by navigating to (?) Help → Command Line Tools → Copy Login Command.

  3. Log in to the cluster, passing in the token to authenticate.

    1. $ oc login --token=<token>

    This identity provider does not support logging in with a user name and password.

  4. Confirm that the user logged in successfully, and display the user name.

    1. $ oc whoami